package com.wang.gulimall.cart.interceptor;

import com.wang.common.vo.MemberResponseVo;
import com.wang.gulimall.cart.to.UserInfoTo;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.UUID;

import static com.wang.common.constant.AuthServerConstant.LOGIN_USER;
import static com.wang.common.constant.CartConstant.TEMP_USER_COOKIE_NAME;
import static com.wang.common.constant.CartConstant.TEMP_USER_COOKIE_TIMEOUT;

/**
 * @Author: wangliuyang
 * @Date: 2021/5/5 15:21
 * @Description:在执行目标方法之前，判断用户的登录状态.并封装传递给controller目标请求
 */

@Component
public class CartInterceptor implements HandlerInterceptor {

    //存放user id/key
    public static ThreadLocal<UserInfoTo> toThreadLocal = new ThreadLocal<>();


    /***
     * 拦截所有请求给ThreadLocal封装UserInfoTo对象
     * 1、从session中获取MemberResponseVo != null，登录状态，为UserInfoTo设置Id
     * 2、从request中获取cookie，找到user-key的value，
     * 目标方法执行之前：在ThreadLocal中存入用户信息【同一个线程共享数据】
     * 从session中获取数据【使用session需要cookie中的GULISESSION 值】
     */
    @Override
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response,
                             Object handler) throws Exception {
        UserInfoTo userInfoTo = new UserInfoTo();
        HttpSession session = request.getSession();
        //从session当中获得当前登录用户的信息
        MemberResponseVo memberResponseVo = (MemberResponseVo) session.getAttribute(LOGIN_USER);
        if (memberResponseVo != null) {
            //用户登录了
            userInfoTo.setUserId(memberResponseVo.getId());
        }
        //是临时用户
        //服务端获取从浏览器传来的cookie
        Cookie[] cookies = request.getCookies();
        if (cookies != null && cookies.length > 0) {
            for (Cookie cookie : cookies) {
                //user-key
                String name = cookie.getName();
                if (name.equals(TEMP_USER_COOKIE_NAME)) {
                    userInfoTo.setUserKey(cookie.getValue());
                    //标记为已是临时用户
                    userInfoTo.setTempUser(true);
                }
            }
        }

        //没有登录的用户第一次
        //如果没有临时用户一定分配一个临时用户
        if (StringUtils.isEmpty(userInfoTo.getUserKey())) {
            String uuid = UUID.randomUUID().toString();
            userInfoTo.setUserKey(uuid);
        }

        //目标方法执行之前
        toThreadLocal.set(userInfoTo);
        return true;
    }

    //业务执行之后，分配临时用户来浏览器保存
    @Override
    public void postHandle(HttpServletRequest request,
                           HttpServletResponse response,
                           Object handler,
                           ModelAndView modelAndView) throws Exception {
        //获取当前用户的值
        UserInfoTo userInfoTo = toThreadLocal.get();

        //如果没有临时用户一定保存一个临时用户
        if (!userInfoTo.getTempUser()) {
            //创建一个cookie
            Cookie cookie = new Cookie(TEMP_USER_COOKIE_NAME, userInfoTo.getUserKey());
            //扩大作用域
            cookie.setDomain("gulimall.com");
            //设置过期时间
            cookie.setMaxAge(TEMP_USER_COOKIE_TIMEOUT);
            response.addCookie(cookie);
        }
    }

    @Override
    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response,
                                Object handler,
                                Exception ex) throws Exception {

    }
}



